An official with knowledge of Friday's shooting at a U.S. school said 27 people were dead, including 18 children. It was the worst school shooting in the country's history. The official spoke on condition of anonymity because the investigation is under way.

Another official, speaking on condition of anonymity for the same reason, said the gunman was among the dead. The White House said President Barack Obama had been notified. The killings happened at Sandy Hook Elementary School in Newtown, about 60 miles (96 kilometers) northeast of New York City.

State police said Newtown police called them around 9:40 a.m. (1340 GMT). Photos from the scene showed young students some crying, others looking frightened being escorted by adults through a parking lot in a line, hands on each other's shoulders. (AP)

Obama speaks to Connecticut governor

President Barack Obama spoke to Connecticut's governor Friday and expressed condolences to those who lost loved ones in the elementary school shooting, the White House said.

White House spokesman Jay Carney would not confirm details of the shooting. Officials with knowledge of the incident said 27 people, including 18 children, were killed.

"As a father, incidents like these weigh heavily on him," White House spokesman Jay Carney said.

Obama was briefed on the shooting Friday morning by his counterterrorism adviser John Brennan and will continue to receive regular updates throughout the day. Carney said the president was likely to address the shooting later Friday.

In addition to his phone call with Connecticut Gov. Dan Malloy, Obama also spoke Friday with FBI director Robert Mueller. The FBI is supporting state and local law enforcement officials in Connecticut as they respond to and investigate the incident.

Carney said the administration would "do everything we can to support state and local law enforcement."

Asked whether the shooting would make gun control a higher priority on the president's agenda, Carney would say only that there would be a day for discussion on that policy issue.